How a Metal Detector Works?

April 27, 2021 Brian 2,003 Comments

Last Updated on July 10, 2024 by Brian

How a metal detector works?

A metal detector is a device that measures the presence of metal in the immediate vicinity. Scanners are useful for locating metal elements inside structures as well as submerged metal objects. A handheld device with a sensing element that can be brushed over the floor or other objects is popular. A shifting sound in the earpieces or a moving needle on a monitor show when the sensor gets close to a chunk of steel.

The method typically gives some measure of distance; the closer the metal is, the louder the sound or the higher the needle goes. In the 1960s, the first commercial metal detectors were produced, and they were widely used for mineral drilling and other industrial purposes.

Land mine detection, as well as the detection of arms including knives and guns, are among the applications (especially in airport security). Metal detectors operate by sending an electric field into the ground from the search coil. Any pieces of metal (targets) that come into contact with the electromagnetic field can become stimulated and emit their own electromagnetic field.

The scanning coil of the sensor collects the retransmitted field and produces a target response, which helps to recognize. Minelab metal detectors can distinguish among various types of objects and can be programmed to disregard unwanted objects. The following data shows the working of detectors:

The search coil of the detector sends an electric current into the soil and receives an electromagnetic field back from a target that helps to locate the different metals that are being searched. The detector’s circuits are housed in the control box. The transmit signal is produced here, and the obtained signal is analyzed and translated here to a target response.

The transmitted signal stimulates the metals underground that makes them be detected, blue color shows the transmit electromagnetic field. The metal detector has a specific target to locate that can be metals and gold. Specific IDs or voice tones specify different targets.

Some unwanted objects can produce a response when attracted to a magnet such as nails but if a metal detector is programmed to reject the response of unwanted objects then a detector will not produce a response to unwanted targets. The obtained signal is generated by the stimulated metals in response to the detectors field and the signal is received by the coil.

The metal detector will generate an auditory response, such as a chirp or a shift in tone, when a successful (accepted) target is detected. A visual display of target information, such as an identification number or a two-dimensional view, is available on many Mine lab detectors.

Transmission at high frequencies locate smaller targets and at low frequencies, deep underground targets are located. Some detectors transmit multiple frequencies at a single time to locate smaller, deeper targets.

Ground balance helps to eliminate the sounds of ground objects other than targets in high mineralized soils. The detectors are also equipped with technologies to discriminate between junk metals and target metals such as gold.

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